text: #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <arpa/inet.h>
  #include <sys/socket.h>
  
  #define BUF_SIZE 100
  int main(){
      //创建套接字
      int sock = socket(AF_INET, SOCK_STREAM, 0);
      //向服务器（特定的IP和端口）发起请求
      struct sockaddr_in serv_addr;
      memset(&serv_addr, 0, sizeof(serv_addr));  //每个字节都用0填充
      serv_addr.sin_family = AF_INET;  //使用IPv4地址
      serv_addr.sin_addr.s_addr = inet_addr("127.0.0.1");  //具体的IP地址
      serv_addr.sin_port = htons(1234);  //端口
      connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
  
      char bufSend[BUF_SIZE] = {0};
      printf("Input a string: ");
      scanf("%s", bufSend);
      send(sock, bufSend, strlen(bufSend), 0);
      //接收服务器传回的数据
      char bufRecv[BUF_SIZE] = {0};
      recv(sock, bufRecv, BUF_SIZE, 0);
      //读取服务器传回的数据
      // char buffer[40];
      // read(sock, buffer, sizeof(buffer)-1);
  
      printf("Message form server: %s\n", bufRecv);
  
      //关闭套接字
      close(sock);
      return 0;
  }
  